Make a rasp board out of plywood and adhere a piece of 60 grit sand paper. The exposed foam won't hold the membrane until you remove the deteriorated foam no matter what adhesive you use.

You might consider spraying or rolling the foam with an elastomeric roof coating. I've experimented with it a bit and it sticks really well to EPS foam. You can stick two pieces of EPS together with this stuff and the foam will break before the bond lets go. This is after cleaning the wall well - I have found that a stiff nylon brush works pretty good, but mine was <1 year old and on the north side of the basement not in direct sunlight.

http://www.gardner-gibson.com/linedetails.aspx?id=87

You want to get a stiff bristled "deck brush" from the home improvement store or a boating store. It will have a long handle on it. You can use that to scrub the surface of the forms to remove the deteriorated EPS. If you have good, drying weather you can also hit it with a hose to help wash down the residue. It'a best as a two person job. Good for laborers, too as it requires minimal supervision - just an occasional quality control check from you.

If you can find a primer before the weekend, you can apply it with a roller. It's like latex paint.

Can you find a Carlisle dealer near you?  They should have stock on CCW702 water-based sheet primer in 5 gal pails.

Little late here, but consider giving it a good bath and then use a liquid applied waterproofing

Thank you everyone for your suggestions.  We ended up hosing the forms down, then brushed them with a soft-bristled brush (the kind you'd use on a car), hosed them down again and allowed them to dry and didn't touch them again until we applied the membrane.  Between that and keeping the membrane out of the sun prior to application, we were able to get a good bond.  It was fairly cool when we were applying the membrane - the temperature was in the low 70's  and it was mid-morning so the sun wasn't very strong - but we still found that if the membrane was warmed by the sun at all it didn't adhere nearly as well as it did if it was kept in the shade.

In the future I would prefer to apply the manufacturer's recommended spray adhesive (or some other compatible primer as suggested by ICFHybrid) but I'm thankful that we were able to get a satisfactory bond without it.

If you are having the peel and stick exposed for any period of time, use red tuck tape to seal the top to help prevent it from peeling. Usually 2 or 3 layers of tape

Is that also known as red, very sticky UV-resistant polypropylene construction tape?